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176-665: See text The Pelagornithidae , commonly called pelagornithids , pseudodontorns , bony-toothed birds , false-toothed birds or pseudotooth birds , are a prehistoric family of large seabirds . Their fossil remains have been found all over the world in rocks dating between the Early Paleocene and the Pliocene - Pleistocene boundary. Most of the common names refer to these birds' most notable trait: tooth-like points on their beak's edges, which, unlike true teeth , contained Volkmann's canals and were outgrowths of

352-525: A cladistic analysis proposed a close relationship between pseudotooth birds and waterfowl (Anseriformes). These are not part of the "higher waterbirds" but of the Galloanserae , a basal lineage of neognath birds. Some features, mainly of the skull, support this hypothesis. For example, the pelagornithids lack a crest on the underside of the palatine bone , while the Neoaves – the sister clade of

528-421: A "net", helping in the capture of flying prey, although to date, there has been no empirical evidence to support this idea. There is some experimental evidence to suggest that they may prevent particles from striking the eyes if, for example, a prey item is missed or broken apart on contact. They may also help to protect the eyes from particles encountered in flight, or from casual contact from vegetation. There

704-402: A "pelecaniform" suborder " Cladornithes ". Those genera known from skull material were typically assigned to one or two families ( Odontopterygidae and sometimes also Pseudodontornithidae ) in a "pelecaniform" suborder Odontopteryges or Odontopterygia . Pelagornis meanwhile, described from wing bones, was traditionally placed in a monotypic "pelecaniform" family Pelagornithidae. This

880-542: A bird; the orangeness of a Montagu's harrier 's cere, for example, correlates to its body mass and physical condition. The cere color of young Eurasian scops-owls has an ultraviolet (UV) component, with a UV peak that correlates to the bird's mass. A chick with a lower body mass has a UV peak at a higher wavelength than a chick with a higher body mass does. Studies have shown that parent owls preferentially feed chicks with ceres that show higher wavelength UV peaks, that is, lighter-weight chicks. The color or appearance of

1056-592: A common impurity. Tin ores are rare, as reflected in the fact there were no tin bronzes in Western Asia before 3000 BCE. The Bronze Age forms part of the three-age system for prehistoric societies. In this system, it follows the Neolithic in some areas of the world. While copper is a common ore, deposits of tin are rare in the Old World , and often had to be traded or carried considerable distances from

1232-415: A complex three-dimensional network of bony spicules (or trabeculae ) seated in soft connective tissue and surrounded by the hard outer layers of the beak. The avian jaw apparatus is made up of two units: one four-bar linkage mechanism and one five-bar linkage mechanism. The upper mandible is supported by a three-pronged bone called the intermaxillary. The upper prong of this bone is embedded into

1408-542: A compromise, rather than in a pelecaniform/ciconiiform or anseriform suborder Odontopterygia or even a family of the Anseriformes, Ciconiiformes or Pelecaniformes. Such a treatment is unlikely to be completely wrong in either case, as the pseudotooth birds are well distinct from the Presbyornithidae and Scopidae , today generally regarded as the very basal divergences of, respectively, the Anseriformes and

1584-401: A convex ventral border to the humeral cotyle , which prominently continues the hind edge of the knob where the biceps brachii muscle attaches; towards the upper side of the radius bone the surface becomes flat and triangular handwards of the articular surface for the ulna. The carpometacarpus of both Anseriformes and pseudotooth birds has a prominent pisiform process, which extends from

1760-436: A dozen types of carotenoids are responsible for the coloration of most red, orange, and yellow beaks. The hue of the color is determined by the precise mix of red and yellow pigments, while the saturation is determined by the density of the deposited pigments. For example, bright red is created by dense deposits of mostly red pigments, while dull yellow is created by diffuse deposits of mostly yellow pigments. Bright orange

1936-410: A few days of hatching, though petrels keep theirs for nearly three weeks and marbled murrelets have theirs for up to a month. Generally, the egg tooth drops off, though in songbirds it is resorbed. The color of a bird's beak results from concentrations of pigments — primarily melanins and carotenoids — in the epidermal layers, including the rhamphotheca. Eumelanin , which is found in

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2112-472: A few rather comprehensive (though much crushed and distorted) remains of individual birds that were entombed by as they lay dead, complete with some fossilized feathers . Large parts of the skull and some beak pieces are found not too infrequently. In February 2009, an almost-complete fossilized skull of a presumed Odontopteryx from around the Chasicoan - Huayquerian boundary c. 9 million years ago (Ma)

2288-543: A large hole. The weakened egg eventually shatters under the pressure of the bird's movements. The egg tooth is so critical to a successful escape from the egg that chicks of most species will perish unhatched if they fail to develop one. However, there are a few species which do not have egg teeth. Megapode chicks have an egg tooth while still in the egg but lose it before hatching, while kiwi chicks never develop one; chicks of both families escape their eggs by kicking their way out. Most chicks lose their egg teeth within

2464-513: A large squirming frog) have very wide nails. Certain types of mechanoreceptors , nerve cells that are sensitive to pressure, vibration, or touch, are located under the nail. The shape or color of the nail can sometimes be used to help distinguish between similar-looking species or between various ages of waterfowl. For example, the greater scaup has a wider black nail than does the very similar lesser scaup . Juvenile " grey geese " have dark nails, while most adults have pale nails. The nail gave

2640-512: A less vivid gape. Conversely, the red gape of the common cuckoo ( Cuculus canorus ) did not induce extra feeding in host parents. Some brood parasites , such as the Hodgson's hawk-cuckoo ( C. fugax ), have colored patches on the wing that mimic the gape color of the parasitized species. When born, the chick's gape flanges are fleshy. As it grows into a fledgling , the gape flanges remain somewhat swollen and can thus be used to recognize that

2816-406: A member of the "higher waterbird" group (see below), they most probably had a plumage similar to that depicted in the reconstruction of Osteodontornis orri – Procellariiformes and Pelecaniformes in the modern sense (or Ciconiiformes , if Pelecaniformes are merged there) have hardly any carotenoid or structural colors at all in their plumage , and generally lack even phaeomelanins . Thus,

2992-496: A membraneous, horny or cartilaginous flap. In diving birds, the operculum keeps water out of the nasal cavity; when the birds dive, the impact force of the water closes the operculum. Some species which feed on flowers have opercula to help to keep pollen from clogging their nasal passages, while the opercula of the two species of Attagis seedsnipe help to keep dust out. The nares of nestling tawny frogmouths are covered with large dome-shaped opercula, which help to reduce

3168-674: A much more evident Mesolithic era, lasting millennia. In Northern Europe , societies were able to live well on rich food supplies from the marshlands fostered by the warmer climate. Such conditions produced distinctive human behaviours that are preserved in the material record, such as the Maglemosian and Azilian cultures. These conditions also delayed the coming of the Neolithic until as late as 4000 BCE (6,000  BP ) in northern Europe. Remains from this period are few and far between, often limited to middens . In forested areas,

3344-450: A number of genera described from leg bones was placed in a family Cyphornithidae , and considered close allies of the pelican family ( Pelecanidae ). They were united with the latter in a superfamily Pelecanides in suborder Pelecanae, or later on (after the endings of taxonomic ranks were fixed to today's standard) Pelecanoidea in suborder Pelecani. Subsequently, some allied them with the entirely spurious "family" " Cladornithidae " in

3520-492: A part of their partner's beak while others clash their beaks vigorously together. Gannets raise their bills high and repeatedly clatter them, the male puffin nibbles at the female's beak, the male waxwing puts his bill in the female's mouth and ravens hold each other's beaks in a prolonged "kiss". Billing can also be used as a gesture of appeasement or subordination. Subordinate Canada jay routinely bill more dominant birds, lowering their body and quivering their wings in

3696-416: A particular bird is young. By the time it reaches adulthood, the gape flanges will no longer be visible. Most species of birds have external nares ( nostrils ) located somewhere on their beak. The nares are two holes—circular, oval or slit-like in shape—which lead to the nasal cavities within the bird's skull, and thus to the rest of the respiratory system . In most bird species, the nares are located in

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3872-404: A reddish or orangish gonydeal spot near the gonydeal expansion. This spot triggers begging behavior in gull chicks. The chick pecks at the spot on its parent's bill, which in turn stimulates the parent to regurgitate food. Depending on its use, commissure may refer to the junction of the upper and lower mandibles, or alternately, to the full-length apposition of the closed mandibles, from

4048-531: A reduced premaxillary bone due to the overdevelopment of the prenasal cartilage, which takes up more mesenchymal cells for cartilage, instead of bone, formation. Different species' beaks have evolved according to their diet; for example, raptors have sharp-pointed beaks that facilitate dissection and biting off of prey animals ' tissue, whereas passerine birds that specialize in eating seeds with especially tough shells (such as grosbeaks and cardinals ) have large, stout beaks with high compressive power (on

4224-651: A sea less wide than the Caribbean is today. Neogene pseudotooth birds are common along the America coasts near the Appalachian and Cordilleran mountains, and these species thus presumably also bred not far offshore or even in the mountains themselves. In that respect the presence of medullary bone in the specimens from Lee Creek Mine in North Carolina , United States, is notable, as among birds this

4400-449: A secreted protein also known to be expressed in mammalian craniofacial development. The combination of these signals determines beak growth along the length, depth, and width axes. Reduced expression of TGFβllr significantly decreased the depth and length of chicken embryonic beak due to the underdevelopment of the premaxillary bone. Contrarily, an increase in Bmp4 signaling would result in

4576-472: A similar underlying structure. Two bony projections – the upper and lower mandibles – are covered with a thin keratinized layer of epidermis known as the rhamphotheca. In most species, two holes called nares lead to the respiratory system. Although the word "beak" was, in the past, generally restricted to the sharpened bills of birds of prey , in modern ornithology , the terms beak and bill are generally considered to be synonymous. The word, which dates from

4752-654: A single room. Settlements might have a surrounding stone wall to keep domesticated animals in and hostile tribes out. Later settlements have rectangular mud-brick houses where the family lived in single or multiple rooms. Burial findings suggest an ancestor cult with preserved skulls of the dead. The Vinča culture may have created the earliest system of writing. The megalithic temple complexes of Ġgantija are notable for their gigantic structures. Although some late Eurasian Neolithic societies formed complex stratified chiefdoms or even states, states evolved in Eurasia only with

4928-749: A single source. The emergence of metallurgy may have occurred first in the Fertile Crescent , where it gave rise to the Bronze Age in the 4th millennium BCE (the traditional view), although finds from the Vinča culture in Europe have now been securely dated to slightly earlier than those of the Fertile Crescent. Timna Valley contains evidence of copper mining 7,000 years ago. The process of transition from Neolithic to Chalcolithic in

5104-456: A small sharp, calcified projection on their beak, which they use to chip their way out of their egg . Commonly known as an egg tooth, this white spike is generally near the tip of the upper mandible, though some species have one near the tip of their lower mandible instead, and a few species have one on each mandible. Despite its name, the projection is not an actual tooth , as the similarly-named projections of some reptiles are; instead, it

5280-405: A strong correlation with summer temperatures recorded in the locations where the sparrows breed; latitude alone showed a much weaker correlation. By dumping excess heat through their bills, the sparrows are able to avoid the water loss which would be required by evaporative cooling—an important benefit in a windy habitat where freshwater is scarce. Several ratites , including the common ostrich ,

5456-463: A waxy structure called a cere (from the Latin cera , which means "wax") or ceroma which covers the base of their bill. This structure typically contains the nares , except in the owls, where the nares are distal to the cere. Although it is sometimes feathered in parrots, the cere is typically bare and often brightly colored. In raptors, the cere is a sexual signal which indicates the "quality" of

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5632-470: A webbed and a hypotrophied hallux being apomorphic and paraphyletic , its absence in pseudotooth birds does not provide much information on their relationship. While giant Galloanserae were common and diverse in the Paleogene in particular, these ( Gastornis and mihirungs ) were flightless terrestrial birds; it is perhaps significant though that the only other "bone-toothed" birds known so far are

5808-404: A woodpecker's nares help to keep wood particles from clogging its nasal passages. Species in the bird order Procellariformes have nostrils enclosed in double tubes which sit atop or along the sides of the upper mandible. These species, which include the albatrosses, petrels, diving petrels, storm petrels, fulmars and shearwaters, are widely known as "tubenoses". A number of species, including

5984-453: Is a selection pressure for an intermediate amount of overhang. Western Scrub Jays who had more symmetrical bills (i.e. those with less of an overhang), were found to have higher amounts of lice when tested. The same pattern has been seen in surveys of Peruvian birds. Additionally, because of the role beaks play in preening, this is evidence for coevolution of the beak overhang morphology and body morphology of parasites. Artificially removing

6160-452: Is a wide platform as in Anseriformes. The bony-toothed birds' attachment of the coronoideal part of the external mandible adductor muscles was located at the midline, the rostropterygoid process had a support at its base and the mesethmoid bone had a deep depression for the caudal concha , just as in waterfowl. As regards other parts of the skeleton , the proposed synapomorphies of pelagornithids and waterfowl are found mainly in

6336-800: Is also a transition period between Stone Age and Bronze Age, the Chalcolithic or Copper Age. For the prehistory of the Americas see Pre-Columbian era . The notion of "prehistory" emerged during the Enlightenment in the work of antiquarians who used the word "primitive" to describe societies that existed before written records. The word "prehistory" first appeared in English in 1836 in the Foreign Quarterly Review . The geologic time scale for pre-human time periods, and

6512-487: Is also evidence that the rictal bristles of some species may function tactilely, in a manner similar to that of mammalian whiskers ( vibrissae ). Studies have shown that Herbst corpuscles , mechanoreceptors sensitive to pressure and vibration, are found in association with rictal bristles. They may help with prey detection, with navigation in darkened nest cavities, with the gathering of information during flight or with prey handling. Full-term chicks of most bird species have

6688-516: Is an example. In archaeology, the Iron Age refers to the advent of ferrous metallurgy . The adoption of iron coincided with other changes, often including more sophisticated agricultural practices, religious beliefs and artistic styles, which makes the archaeological Iron Age coincide with the " Axial Age " in the history of philosophy. Although iron ore is common, the metalworking techniques necessary to use iron are different from those needed for

6864-488: Is anonymous. Because of this, reference terms that prehistorians use, such as " Neanderthal " or " Iron Age ", are modern labels with definitions sometimes subject to debate. The concept of a "Stone Age" is found useful in the archaeology of most of the world, although in the archaeology of the Americas it is called by different names and begins with a Lithic stage , or sometimes Paleo-Indian . The sub-divisions described below are used for Eurasia, and not consistently across

7040-782: Is called the Lower Paleolithic (as in excavations it appears underneath the Upper Paleolithic), beginning with the earliest stone tools dated to around 3.3 million years ago at the Lomekwi site in Kenya. These tools predate the genus Homo and were probably used by Kenyanthropus . Evidence of control of fire by early hominins during the Lower Palaeolithic Era is uncertain and has at best limited scholarly support. The most widely accepted claim

7216-501: Is created by dense deposits of both red and yellow pigments, in roughly equal concentrations. Beak coloration helps to make displays using those beaks more obvious. In general, beak color depends on a combination of the bird's hormonal state and diet . Colors are typically brightest as the breeding season approaches, and palest after breeding. Birds are capable of seeing colors in the ultraviolet range, and some species are known to have ultraviolet peaks of reflectance (indicating

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7392-430: Is generally only found in laying females, indicating that the breeding grounds were probably not far away. At least Pacific islands of volcanic origin would be eroded away in the last millions of years however, obliterating any remains of pelagornithid breeding colonies that might have once existed in the open ocean. Necker Island for example was of significant size 10 million years ago, when Osteodontornis roamed

7568-588: Is notable that the most basal lineages of Anseriformes are typically grey-and-black or black-and-white. Among ocean-going birds in general, the upperside tends to be much darker than the underside (including the underwings) – though some petrels are dark grey all over, a combination of more or less dark grey upperside and white underside and (usually) head is a widespread colouration found in seabirds and may either be plesiomorphic for "higher waterbirds" or, perhaps more likely, be an adaptation to provide camouflage , in particular against being silhouetted against

7744-601: Is one of the few species of mammals to use electroreception . The beaks of aquatic birds contain Grandry corpuscles , which assist in velocity detection while filter feeding. The beak of birds plays a role in removing skin parasites ( ectoparasites ) such as lice. It is mainly the tip of the beak that does this. Studies have shown that inserting a bit to stop birds from using the tip results in increased parasite loads in pigeons. Birds that have naturally deformed beaks have also been noted to have higher levels of parasites. It

7920-449: Is part of the integumentary system , as are claws and scales . The hatching chick first uses its egg tooth to break the membrane around an air chamber at the wide end of the egg. Then it pecks at the eggshell while turning slowly within the egg, eventually (over a period of hours or days) creating a series of small circular fractures in the shell. Once it has breached the egg's surface, the chick continues to chip at it until it has made

8096-558: Is provided by a wide variety of natural and social sciences, such as anthropology , archaeology , archaeoastronomy , comparative linguistics , biology , geology , molecular genetics , paleontology , palynology , physical anthropology , and many others. Human prehistory differs from history not only in terms of its chronology , but in the way it deals with the activities of archaeological cultures rather than named nations or individuals . Restricted to material processes, remains, and artefacts rather than written records, prehistory

8272-551: Is seen as a transition period between the Stone Age and Bronze Age. An archaeological site in Serbia contains the oldest securely dated evidence of copper making at high temperature, from 7,500 years ago. The find in 2010 extends the known record of copper smelting by about 800 years, and suggests that copper smelting may have been invented independently in separate parts of Asia and Europe at that time, rather than spreading from

8448-500: Is that H. erectus or H. ergaster made fires between 790,000 and 690,000 BP in a site at Bnot Ya'akov Bridge , Israel . The use of fire enabled early humans to cook food, provide warmth, have a light source, deter animals at night and meditate. Early Homo sapiens originated some 300,000 years ago, ushering in the Middle Palaeolithic . Anatomic changes indicating modern language capacity also arise during

8624-489: Is the period of human history between the first known use of stone tools by hominins c.  3.3   million years ago and the beginning of recorded history with the invention of writing systems . The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared c.  5,200 years ago. It took thousands of years for writing systems to be widely adopted, with writing having spread to almost all cultures by

8800-538: Is thought that the overhang at the end of the top portion of the beak (that is the portion that begins to curve downwards) slides against the lower beak to crush parasites. This overhang of the beak is thought to be under stabilising natural selection . Very long beaks are thought to be selected against because they are prone to a higher number of breaks, as has been demonstrated in rock pigeons. Beaks with no overhang would be unable to effectively remove and kill ectoparasites as mentioned above. Studies have supported there

8976-435: Is typically a septum made of bone or cartilage that separates the two nares, but in some families (including gulls, cranes and New World vultures), the septum is missing. While the nares are uncovered in most species, they are covered with feathers in a few groups of birds, including grouse and ptarmigans, crows, and some woodpeckers. The feathers over a ptarmigan's nostrils help to warm the air it inhales, while those over

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9152-516: Is when the first signs of human presence have been found; however, Africa and Asia contain sites dated as early as c.  2.5 and 1.8 million years ago, respectively. Depending on the date when relevant records become a useful academic resource, its end date also varies. For example, in Egypt it is generally accepted that prehistory ended around 3100 BCE, whereas in New Guinea

9328-471: The Antarctic . It is conspicuous that penguins and plotopterids – both wing-propelled divers that foraged over the continental shelf – are almost invariably found in the company of pseudotooth birds. Thus, pseudotooth birds seem to have gathered in some numbers in upwelling regions, presumably to feed but perhaps also to breed nearby. It is sometimes claimed that as with some other seabirds (e.g.

9504-747: The Atlantic off the Eastern Seaboard , while the Pacific Osteodontornis inhabited the same seas as Balaenula and Morenocetus ; the ancestral smallish sperm whale genus Aulophyseter (and/or Orycterocetus ) occurred in both Northern Hemisphere oceans at that time, while the mid-sized sperm whale Brygmophyseter roamed the North Pacific. As regards Miocene pinnipeds, a diversity of ancient walruses and ancestral fur seals like Thalassoleon inhabited

9680-554: The Ciconiiformes (storks and/or either herons and ibises or the "core" Pelecaniformes) and Gaviiformes (loons/divers) seem to make up a radiation , possibly a clade , of "higher waterbirds". However, the Pelagornithidae are not generally held to be a missing link between pelicans and albatrosses anymore, but if anything much closer to the former and only convergent to the latter in ecomorphology . In 2005,

9856-708: The Copper Age or Bronze Age ; or, in some geographical regions, in the Iron Age ). The term Neolithic is commonly used in the Old World ; its application to cultures in the Americas and Oceania is complicated by the fact standard progression from stone to metal tools, as seen in the Old World, does not neatly apply. Early Neolithic farming was limited to a narrow range of plants, both wild and domesticated, which included einkorn wheat , millet and spelt , and

10032-592: The Messinian Salinity Crisis did affect the trophic web of Earth's oceans not insignificantly either, and the latter event led to a widespread extinction of seabirds. Together, this combination of factors led to Neogene animals finally replacing the last remnants of the Paleogene fauna in the Pliocene. In that respect, it is conspicuous that the older pseudotooth birds are typically found in

10208-486: The Paleocene - Eocene boundary of Morocco – is the smallest pseudotooth bird discovered to date and was just a bit larger than a white-chinned petrel ( Procellaria aequinoctialis ). The Pelagornithidae had extremely thin-walled bones widely pneumatized with the air sac extensions of the lungs . Most limb bone fossils are very much crushed for that reason. In life, the thin bones and extensive pneumatization enabled

10384-531: The Paleolithic , by the Neolithic only Homo sapiens sapiens remained. This was a period of technological and social developments which established most of the basic elements of historical cultures, such as the domestication of crops and animals , and the establishment of permanent settlements and early chiefdoms. The era commenced with the beginning of farming , which produced the " Neolithic Revolution ". It ended when metal tools became widespread (in

10560-565: The Procellariiformes (tube-nosed seabirds like albatrosses and petrels ), because of their similar general anatomy . Some of the first remains of the massive Dasornis were mistaken for a ratite and later a gastornithid . They were even used to argue for a close relationship between these two groups – and indeed, the pelicans and tubenoses, as well as for example the other "Pelecaniformes" ( cormorants and allies) which are preferably separated as Phalacrocoraciformes nowadays,

10736-637: The Ypresian London Clay of the Isle of Sheppey , wherein pelagornithid fossils are not infrequently found, it was deposited in a shallow epicontinental sea during a very hot time with high sea levels . The presumed breeding sites cannot have been as far offshore as many seabird rookeries are today, as the region was hemmed in between the Alps and the Grampian and Scandinavian Mountains , in

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10912-483: The beaks are robust and distinctive enough to allow for good taxonomic delimitation, and even these are usually found as broken pieces. For example, Argilliornis and Neptuniavis were recently found to be arm and leg bones, respectively, of Dasornis , which until then was only known from skull bones. Size is generally regarded as reliable marker for generic diversity, but care just be taken to ascertain whether smallish specimens are not from young birds. Tentatively,

11088-409: The bill . The phylogenetic uncertainties surrounding them do not allow to infer whether the bony-toothed birds had a throat sac similar to pelicans. If they did, it was probably red or orange, and may have been used in mating displays . Sexual dimorphism was probably almost nonexistent, as it typically is among the basal Anseriformes and the "higher waterbirds". The name "pseudodontorns" refers to

11264-532: The carpal trochlea far fingerwards along the bone's forward side. On the carpometacarpus' underside, there is a long but narrow symphysis of the distal metacarpals , with the large metacarpal bone having a mid-ridge that at its outer end curves tailwards, and the thumb joint has a well-developed knob on the hind side of its articular surface. The leg and foot bones, as is to be expected from birds not as specialized for swimming as waterfowl are, show less similarities between Anseriformes and pseudotooth birds: on

11440-701: The emu and the southern cassowary , use various bare parts of their bodies (including their beaks) to dissipate as much as 40% of their metabolic heat production. Alternately, studies have shown that birds from colder climates (higher altitudes or latitudes and lower environmental temperatures) have smaller beaks, lessening heat loss from that structure. During courtship, mated pairs of many bird species touch or clasp each other's bills. Termed billing (also nebbing in British English), this behavior appears to strengthen pair bonding . The amount of contact involved varies among species. Some gently touch only

11616-572: The falcons , have a small bony tubercule which projects from their nares. The function of this tubercule is unknown. Some scientists suggest it may act as a baffle, slowing down or diffusing airflow into the nares (and thus allowing the bird to continue breathing without damaging its respiratory system) during high-speed dives, but this theory has not been proved experimentally. Not all species that fly at high speeds have such tubercules, while some species which fly at low speeds do. The nares of some birds are covered by an operculum (plural opercula ),

11792-585: The flightless Plotopteridae ), the evolutionary radiation of cetaceans and pinnipeds outcompeted the pseudotooth birds and drove them into extinction . While this may be correct for the plotopterids, for pelagornithids it is not so likely for two reasons: First, the Pelagornithidae continued to thrive for 10 million years after modern-type baleen whales evolved , and in the Middle Miocene Pelagornis coexisted with Aglaocetus and Harrison's whale ( Eobalaenoptera harrisoni ) in

11968-416: The genus Pseudodontornis , which for some time served as the family 's namesake. However, the presently used name Pelagornithidae pre-dates Pseudodontornithidae, and thus modern authors generally prefer "pelagornithids" over "pseudodontorns". The latter name is generally found in mid-20th-century literature however. Historically, the disparate bones of the pseudotooth birds were spread across six groups:

12144-548: The noisy miner , use bill clapping as a form of communication. Some woodpecker species are known to use percussion as a courtship activity, whereas males will get the ( aural ) attention of females from a distance and then impress them with the sound volume and pattern. This explains why humans are sometimes inconvenienced by pecking that clearly has no feeding purpose (such as when the bird pecks on sheet metal repeatedly). Studies have shown that some birds use their beaks to rid themselves of excess heat. The toco toucan , which has

12320-485: The premaxillary and mandibular bones. Even "small" species of pseudotooth birds were the size of albatrosses ; the largest ones had wingspans estimated at 5–6 metres (15–20 ft) and were among the largest flying birds ever to live. They were the dominant seabirds of most oceans throughout most of the Cenozoic , and modern humans apparently missed encountering them only by a tiny measure of evolutionary time:

12496-579: The ratites . Here, the vomer is large and connects with premaxillae and maxillopalatine bones in a condition termed as a "paleognathous palate". All other extant birds have a narrow forked vomer that does not connect with other bones and is then termed as neognathous. The shape of these bones varies across the bird families. The lower mandible is supported by a bone known as the inferior maxillary bone—a compound bone composed of two distinct ossified pieces. These ossified plates (or rami ), which can be U-shaped or V-shaped, join distally (the exact location of

12672-408: The selective forces brought about by skimming food from the upper water layer. The apparent non-neoavian traits distinguishing pelagornithids could just as well be retained or atavistic plesiomorphies ; as the "higher waterbirds" are very ancient Neoaves and none of the suspected basal members of their radiation (see also " Graculavidae ") were included in the analysis, it is not known for sure when

12848-578: The snaggletooth shark Hemipristis serra , tiger sharks ( Galeocerdo ), Carcharhinus whaler sharks, the lemon shark ( Negaprion brevirostris ) and hammerhead sharks ( Sphyrna ), and perhaps (depending on the bird fossils' age) also Pristis sawfishes, Odontaspis sand tiger sharks, and Lamna and Parotodus benedeni mackerel sharks. It is notable that fossils of smaller diving birds – for example auks, loons and cormorants – as well as those of albatrosses are much more commonly found in those shark pellets than pseudotooth birds, supporting

13024-606: The three-age system for human prehistory, were systematised during the nineteenth century in the work of British, French, German, and Scandinavian anthropologists , archaeologists , and antiquarians . The main source of information for prehistory is archaeology (a branch of anthropology), but some scholars are beginning to make more use of evidence from the natural and social sciences. The primary researchers into human prehistory are archaeologists and physical anthropologists who use excavation, geologic and geographic surveys, and other scientific analysis to reveal and interpret

13200-496: The tibiotarsus there is a wide incision between the condyles and the middle condyle is narrower than the side condyle and protrudes forwards; the tarsometatarsus has a low distal vascular foramen with recessed opening on its plantar surface and a middle toe trochlea that is elongated, slightly oblique , projects to the underside of the foot and is pointed at the tip. It is unclear what to make of these apomorphies supposedly uniting Anseriformes and bony-toothed birds, for on

13376-475: The "Chalcolithic", "Eneolithic", or "Copper Age" refers to a transitional period where early copper metallurgy appeared alongside the widespread use of stone tools. During this period, some weapons and tools were made of copper. This period was still largely Neolithic in character. It is a phase of the Bronze Age before it was discovered that adding tin to copper formed the harder bronze . The Copper Age

13552-402: The (then-paraphyletic) "Pelecaniformes", but in particular the tarsometatarsus was typically mistaken for that of a procellariiform. The Odontopterygiformes were first proposed when Osteodontornis was described from the first – and still the only known – reasonably complete skeleton of one of these birds. Hildegarde Howard found that, no matter that some of its features resembled other birds,

13728-548: The 13th century, comes from the Middle English bec (via Anglo French ), which itself comes from the Latin beccus . Although beaks vary significantly in size and shape from species to species, their underlying structures have a similar pattern. All beaks are composed of two jaws, generally known as the maxilla (upper) and mandible (lower). The upper, and in some cases the lower, mandibles are strengthened internally by

13904-623: The 19th century. The end of prehistory therefore came at different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age , Sumer in Mesopotamia , the Indus Valley Civilisation , and ancient Egypt were the first civilizations to develop their own scripts and keep historical records, with their neighbours following. Most other civilizations reached their end of prehistory during

14080-623: The Americas, these areas did not develop complex writing systems before the arrival of Eurasians, so their prehistory reaches into relatively recent periods; for example, 1788 is usually taken as the end of the prehistory of Australia . The period when a culture is written about by others, but has not developed its own writing system, is often known as the protohistory of the culture. By definition, there are no written records from human prehistory, which can only be known from material archaeological and anthropological evidence: prehistoric materials and human remains. These were at first understood by

14256-540: The Anseriformes. Also, the pelagornithid Palaeochenoides mioceanus was initially mistaken for an anseriform, and the same might hold true for the supposed Oligocene swan Guguschia nailiae . In the former case, however, a "much the more convincing" analysis for a placement outside the Galloanseres was published the year after its description already. Most unrecognised pelagornithid bones were initially assigned to "higher waterbird" families however, typically to

14432-705: The Azilian cultures, before spreading to Europe through the Iberomaurusian culture of Northern Africa and the Kebaran culture of the Levant . However, independent discovery is not ruled out. "Neolithic" means "New Stone Age", from about 10,200 BCE in some parts of the Middle East, but later in other parts of the world, and ended between 4,500 and 2,000 BCE. Although there were several species of humans during

14608-545: The Galloanserae which includes the "higher waterbirds" and the "higher landbirds" – have such a crest. Also, like ducks, geese and swans pelagornithids only have two and not three condyles on the mandibular process of the quadrate bone , with the middle condyle beakwards of the side condyle. Their basipterygoid articulation is similar to that of the Galloanseres. At the side of the parasphenoid lamina , there

14784-460: The Iron Age, often through conquest by empires, which continued to expand during this period. For example, in most of Europe conquest by the Roman Empire means the term Iron Age is replaced by "Roman", " Gallo-Roman ", and similar terms after the conquest. Even before conquest, many areas began to have a protohistory, as they were written about by literate cultures; the protohistory of Ireland

14960-694: The Middle East is characterized in archaeological stone tool assemblages by a decline in high quality raw material procurement and use. North Africa and the Nile Valley imported its iron technology from the Near East and followed the Near Eastern course of Bronze Age and Iron Age development. The Bronze Age is the earliest period in which some civilizations reached the end of prehistory, by introducing written records. The Bronze Age, or parts thereof, are thus considered to be part of prehistory only for

15136-739: The Middle Palaeolithic. During the Middle Palaeolithic Era, there is the first definitive evidence of human use of fire. Sites in Zambia have charred logs, charcoal and carbonized plants, that have been dated to 180,000 BP. The systematic burial of the dead , music , prehistoric art , and the use of increasingly sophisticated multi-part tools are highlights of the Middle Paleolithic. The Upper Paleolithic extends from 50,000 and 12,000 years ago, with

15312-641: The Pacific. There is no obvious single reason for the pseudotooth birds' extinction. A scenario of general ecological change – exacerbated by the beginning ice age and changes in ocean currents due to plate tectonic shifts (e.g. the emergence of the Antarctic circumpolar current or the closing of the Isthmus of Panama ) – is more likely, with the pseudotooth birds as remnants of the world's Paleogene fauna ultimately failing to adapt . In that respect it may be significant that some lineages of cetaceans, like

15488-496: The Pelagornithidae. Irrespective of the cause of their ultimate extinction, during the long time of their existence the pseudotooth birds furnished prey for large predators themselves. Few if any birds that coexisted with them were large enough to harm them while airborne; as evidenced by the Early Eocene Limnofregata , the frigatebirds coevolved with the Pelagornithidae and may well have harassed any of

15664-439: The ability to preen in birds, followed by readdition of preening ability was shown to result in changes in body size in lice. Once the ability of the birds to preen was reintroduced, the lice were found to show declines in body size suggesting they may evolve in response to preening pressures from birds who could respond in turn with changes in beak morphology. A number of species, including storks , some owls , frogmouths and

15840-431: The analysis does not recover the correct phylogeny and does not include the shoebill ( Balaeniceps rex , a "missing link" between pelicans and storks) either; clearly, the adaptive radiation of the pelican-stork lineage is misleading the analysis here. In addition, the Galloanserae are not recovered as monophyletic . In 2007, a far more comprehensive cladistic analysis of bird anatomy including some fossil forms (though not

16016-438: The arm- and handbones: the ulna had a strongly convex upper backside at its elbow end – at the handward end of which the scapulotricipital muscles attached –, a point-tipped dorsal cotyle and only a shallow depression to house the meniscus between ulna and radius ; towards the elbow, the intercondylar sulcus of the ulna becomes wide and is bordered by a long winding ridge on the belly side. The radius, meanwhile, has

16192-459: The assumption that the latter had quite low population densities and caught much of their food in mid-flight. A study on Pelagornis ' flight performance suggests that, unlike modern seabirds, it relied on thermal soaring much like continental soaring birds and Pteranodon . Nothing is known for sure about the colouration of these birds, as they left no living descendants. But some inferences can be made based on their phylogeny : if they were

16368-464: The bare parts of many bird species, is responsible for all shades of gray and black; the denser the deposits of pigment found in the epidermis, the darker the resulting color. Phaeomelanin produces "earth tones" ranging from gold and rufous to various shades of brown. Although it is thought to occur in combination with eumelanin in beaks which are buff, tan, or horn-colored, researchers have yet to isolate phaeomelanin from any beak structure. More than

16544-424: The basal third of the upper mandible. Kiwi are a notable exception; their nares are located at the tip of their bills. A handful of species have no external nares. Cormorants and darters have primitive external nares as nestlings, but these close soon after the birds fledge ; adults of these species (and gannets and boobies of all ages, which also lack external nostrils) breathe through their mouths. There

16720-511: The beak. This shield -shaped structure, which sometimes spans the entire width of the beak, is often bent at the tip to form a hook. It serves different purposes depending on the bird's primary food source. Most species use their nails to dig seeds out of mud or vegetation, while diving ducks use theirs to pry molluscs from rocks. There is evidence that the nail may help a bird to grasp objects. Species which use strong grasping motions to secure their food (such as when catching and holding onto

16896-401: The bill" and runs from the point where the upper mandible emerges from the forehead's feathers to its tip. The bill's length along the culmen is one of the regular measurements made during bird banding (ringing) and is particularly useful in feeding studies. There are several standard measurements that can be made—from the beak's tip to the point where feathering starts on the forehead, from

17072-486: The bill, above the nares; though it is sometimes referred to as the cere , this is a different structure. Tapaculos are the only birds known to have the ability to move their opercula. Some species, such as the puffin , have a fleshy rosette, sometimes called a "gape rosette", at the corners of the beak. In the puffin, this is grown as part of its display plumage. Birds from a handful of families—including raptors, owls, skuas, parrots, turkeys and curassows—have

17248-446: The bird to slice through a seed's outer hull . Most falcons have a sharp projection along the upper mandible, with a corresponding notch on the lower mandible. They use this "tooth" to sever their prey's vertebrae fatally or to rip insects apart. Some kites , principally those that prey on insects or lizards, also have one or more of these sharp projections, as do the shrikes . The tomial teeth of falcons are underlain by bone, while

17424-399: The birds and pinnipeds would need level ground near the sea to raise their young, competition for breeding grounds may have affected the birds' population. In that respect, the specializations for dynamic soaring restricted the number of possible nesting sites for the birds, but on the other hand upland on islands or in coastal ranges could have provided breeding grounds for Pelagornithidae that

17600-401: The birds to achieve large size while remaining below critical wing loadings . Though 25 kg/m (5 lb/ft) is regarded as the maximum wing loading for powered bird flight, there is evidence that bony-toothed birds used dynamic soaring flight almost exclusively: the proximal end of the humerus had an elongated diagonal shape that could hardly have allowed for the movement necessary for

17776-410: The breeding season. While most extant birds have a single seamless rhamphotheca, species in a few families, including the albatrosses and the emu , have compound rhamphothecae that consist of several pieces separated and defined by softer keratinous grooves. Studies have shown that this was the primitive ancestral state of the rhamphotheca, and that the modern simple rhamphotheca resulted from

17952-501: The brush-like projections may help to increase the coefficient of friction between the mandibles, thereby improving the bird's ability to hold hard prey items. Serrations on hummingbird bills, found in 23% of all hummingbird genera, may perform a similar function, allowing the birds to effectively hold insect prey. They may also allow shorter-billed hummingbirds to function as nectar thieves , as they can more effectively hold and cut through long or waxy flower corollas . In some cases,

18128-569: The case of Indigenous Australian "highways" known as songlines . The Mesolithic, or Middle Stone Age (from the Greek mesos , 'middle', and lithos , 'stone'), was a period in the development of human technology between the Palaeolithic and Neolithic . The Mesolithic period began with the retreat of glaciers at the end of the Pleistocene epoch, some 10,000 BP, and ended with

18304-401: The cere can be used to distinguish between males and females in some species. For example, the male great curassow has a yellow cere, which the female (and young males) lack. The male budgerigar 's cere is royal blue, while the female's is a very pale blue, white, or brown. All birds of the family Anatidae (ducks, geese, and swans) have a nail , a plate of hard horny tissue at the tip of

18480-463: The collection of folklore and by analogy with pre-literate societies observed in modern times. The key step to understanding prehistoric evidence is dating, and reliable dating techniques have developed steadily since the nineteenth century. The most common of these dating techniques is radiocarbon dating . Further evidence has come from the reconstruction of ancient spoken languages . More recent techniques include forensic chemical analysis to reveal

18656-412: The color of a bird's tomia can help to distinguish between similar species. The snow goose , for example, has a reddish-pink bill with black tomia, while the whole beak of the similar Ross's goose is pinkish-red, without darker tomia. The culmen is the dorsal ridge of the upper mandible. Likened by ornithologist E. Coues to the ridge line of a roof, it is the "highest middle lengthwise line of

18832-407: The combination was quite unlike any neognath known. While the authors claim it is beyond the paper's scope, the study describing Protodontopteryx suggests that the proposed pro-galloansere traits might actually be plesiomorphic in relation to Aves. It also notes "striking" similarities between pelagornithids and Ichthyornis in terms of jaw anatomy, but still classifies them as neognaths due to

19008-518: The corners of the mouth to the tip of the beak. In bird anatomy , the gape is the interior of the open mouth of a bird, and the gape flange is the region where the two mandibles join together at the base of the beak. The width of the gape can be a factor in the choice of food. Gapes of juvenile altricial birds are often brightly coloured, sometimes with contrasting spots or other patterns, and these are believed to be an indication of their health, fitness and competitive ability. Based on this,

19184-409: The crucial Late Cretaceous taxa, which are usually known only from fragmentary remains) resolved the "higher waterbird" radiation somewhat better; still, the problem of leg and foot traits confounding the analysis was noticeable. As their relationships are still unresolved between Galloanserae and "higher waterbirds", the pseudotooth birds are here placed in the distinct order Odontopterygiformes as

19360-410: The culmen can also help with the identification of birds in the field. For example, the culmen of the parrot crossbill is strongly decurved, while that of the very similar red crossbill is more moderately curved. The culmen of a juvenile common loon is all dark, while that of the very similarly plumaged juvenile yellow-billed loon is pale towards the tip. The gonys is the ventral ridge of

19536-515: The derived conditions typical of modern Neoaves were acquired. Footbone traits are notoriously prone to selection forces in birds, with convergent evolution known to inhibit or even invalidate cladistic analyses; however, the apparent autapomorphies of the lower arm and hand bones are hard to explain by anything else than an actual relationship. The location of the salt glands inside the eye sockets of Osteodontornis , Pelagornis (and probably others) shows that whatever their relationships were,

19712-506: The end of the Bronze Age large states, whose armies imposed themselves on people with a different culture, and are often called empires, had arisen in Egypt, China, Anatolia (the Hittites ), and Mesopotamia , all of them literate. The Iron Age is not part of prehistory for all civilizations who had introduced written records during the Bronze Age. Most remaining civilizations did so during

19888-639: The end of the prehistoric era is set much more recently, in the 1870s, when the Russian anthropologist Nicholai Miklukho-Maklai spent several years living among native peoples, and described their way of life in a comprehensive treatise. In Europe the relatively well-documented classical cultures of Ancient Greece and Ancient Rome had neighbouring cultures, including the Celts and the Etruscans , with little writing. Historians debate how much weight to give to

20064-446: The few mines, stimulating the creation of extensive trading routes. In many areas as far apart as China and England, the valuable new material was used for weapons, but for a long time apparently not available for agricultural tools. Much of it seems to have been hoarded by social elites, and sometimes deposited in extravagant quantities, from Chinese ritual bronzes and Indian copper hoards , to European hoards of unused axe-heads. By

20240-493: The first organized settlements and blossoming of artistic work. Throughout the Palaeolithic, humans generally lived as nomadic hunter-gatherers . Hunter-gatherer societies tended to be very small and egalitarian, although hunter-gatherer societies with abundant resources or advanced food-storage techniques sometimes developed sedentary lifestyles with complex social structures such as chiefdoms, and social stratification . Long-distance contacts may have been established, as in

20416-497: The first signs of deforestation have been found, although this would only begin in earnest during the Neolithic, when more space was needed for agriculture . The Mesolithic is characterized in most areas by small composite flint tools: microliths and microburins . Fishing tackle , stone adzes , and wooden objects such as canoes and bows have been found at some sites. These technologies first occur in Africa, associated with

20592-409: The flight feathers, the large amount of melanin gives them better resistance against being damaged in flight. In soaring birds as dependent on strong winds as the bony-toothed birds were, black wingtips and perhaps tails can be expected to have been present. As regards the bare parts, all the presumed close relatives of the Pelagornithidae quite often have rather bright reddish colours, in particular on

20768-461: The following Iron Age . The three-age division of prehistory into Stone Age , Bronze Age , and Iron Age remains in use for much of Eurasia and North Africa , but is not generally used in those parts of the world where the working of hard metals arrived abruptly from contact with Eurasian cultures, such as Oceania , Australasia , much of Sub-Saharan Africa , and parts of the Americas . With some exceptions in pre-Columbian civilizations in

20944-586: The following genera are recognized: Some other Paleogene (and in one case possibly Late Cretaceous ) birds, typically taxa known only from the most fragmentary remains, might also be pelagornithids. They are not usually placed here, but the fossils' large size and the known similarities of certain pseudotooth birds' bones to those of other lineages warrant further study. The genera in question are Laornis , Proceriavis , Manu and Protopelicanus . [REDACTED] [REDACTED] Prehistoric Prehistory , also called pre-literary history ,

21120-404: The forehead, while the two lower prongs attach to the sides of the skull . At the base of the upper mandible a thin sheet of nasal bones is attached to the skull at the nasofrontal hinge, which gives mobility to the upper mandible, allowing it to move upward and downward. The base of the upper mandible, or the roof when seen from the mouth, is the palate, the structure of which differs greatly in

21296-419: The formation of teeth in other dinosaurs. This might have an importance to their actual phylogenetic position. A 2022 paper described Janavis , an ichthyornithine (advanced stem-bird) with a pterygoid bone similar to that of galloanserans. This implies that a galloanseran-like pterygoid is ancestral for crown-group birds as a whole, rather than a derived feature of neognaths. The authors noted that among

21472-415: The gape coloration, and other factors influencing their decision remain unknown. Red gape color has been shown in several experiments to induce feeding. An experiment in manipulating brood size and immune system with barn swallow nestlings showed the vividness of the gape was positively correlated with T-cell –mediated immunocompetence , and that larger brood size and injection with an antigen led to

21648-605: The genus Neptuniavis and assigned to the Procellariidae in the Procellariiformes. All these remains were only shown to belong in the pseudotooth bird genus Dasornis in 2008. The most basal known pelagornithid is Protodontopteryx . The systematics of bony-toothed birds are subject of considerable debate. Initially, they were allied with the (then- polyphyletic ) " Pelecaniformes " ( pelicans and presumed allies, such as gannets and frigatebirds ) and

21824-403: The gradual loss of the defining grooves through evolution. The tomia (singular tomium ) are the cutting edges of the two mandibles. In most birds, these range from rounded to slightly sharp, but some species have evolved structural modifications that allow them to handle their typical food sources better. Granivorous (seed-eating) birds, for example, have ridges in their tomia, which help

22000-438: The groups often regarded as galloanserans based on their pterygoid morphology (pelagornithids, dromornithids and gastornithids ), some might instead constitute early-diverging crown-birds outside Galloanserae, or even be outside the avian crown group altogether. Due to the fragmented and crushed state of most pseudotooth bird remains, it is not clear whether the roughly one dozen genera that have been named are all valid. Only

22176-473: The introduction of agriculture , the date of which varied by geographic region. In some areas, such as the Near East , agriculture was already underway by the end of the Pleistocene , and there the Mesolithic is short and poorly defined. In areas with limited glacial impact, the term " Epipalaeolithic " is preferred. Regions that experienced greater environmental effects as the last ice age ended have

22352-483: The jaw muscles of similarly sized mammals. The outer surface of the beak consists of a thin sheath of keratin called the rhamphotheca , which can be subdivided into the rhinotheca of the upper mandible and the gnathotheca of the lower mandible. This covering arises from the Malpighian layer of the bird's epidermis , growing from plates at the base of each mandible. There is a vascular layer between

22528-549: The joint depends on the species) but are separated proximally , attaching on either side of the head to the quadrate bone. The jaw muscles, which allow the bird to close its beak, attach to the proximal end of the lower mandible and to the bird's skull. The muscles that depress the lower mandible are usually weak, except in a few birds such as the starlings and the extinct huia , which have well-developed digastric muscles that aid in foraging by prying or gaping actions. In most birds, these muscles are relatively small as compared to

22704-474: The keeping of dogs , sheep , and goats . By about 6,900–6,400 BCE, it included domesticated cattle and pigs, the establishment of permanently or seasonally inhabited settlements, and the use of pottery . The Neolithic period saw the development of early villages , agriculture , animal domestication , tools , and the onset of the earliest recorded incidents of warfare. Settlements became more permanent, some with circular houses made of mudbrick with

22880-479: The largest beak relative to the size of its body of any bird species, is capable of modifying the blood flow to its beak. This process allows the beak to work as a "transient thermal radiator", reportedly rivaling an elephant's ears in its ability to radiate body heat. Measurements of the bill sizes of several species of American sparrows found in salt marshes along the North American coastlines show

23056-545: The last known pelagornithids were contemporaries of Homo habilis and the beginning of the history of technology . The biggest of the pseudotooth birds were the largest flying birds known. Almost all of their remains from the Neogene are immense, but in the Paleogene there were a number of pelagornithids that were around the size of a great albatross ( genus Diomedea ) or even a bit smaller. The undescribed species provisionally called " Odontoptila inexpectata " – from

23232-496: The lower jaw resembled that of a pelican or other birds that can open their beak widely. Altogether, the pseudotooth birds would have filled an ecological niche almost identical to that of the larger fish-eating pteranodontian pterosaurs , whose extinction at the end of the Cretaceous may well have paved the way for the highly successful 50-million-year reign of the Pelagornithidae. Like them as well as modern albatrosses ,

23408-451: The lower mandible, created by the junction of the bone's two rami, or lateral plates. The proximal end of that junction—where the two plates separate—is known as the gonydeal angle or gonydeal expansion . In some gull species, the plates expand slightly at that point, creating a noticeable bulge; the size and shape of the gonydeal angle can be useful in identifying between otherwise similar species. Adults of many species of large gulls have

23584-403: The lower ones hidden behind them. Inside the eye sockets of at least some pseudotooth birds – perhaps only in the younger species – were well-developed salt glands . Altogether, almost no major body part of pelagornithids is known from a well-preserved associated fossil and most well-preserved material consists of single bones only; on the other hand the long occurrence and large size makes for

23760-716: The male garganey touches his beak to the blue speculum feathers on his wings in a fake preening display, and the male Mandarin duck does the same with his orange sail feathers. A number of species use a gaping, open beak in their fear and/or threat displays. Some augment the display by hissing or breathing heavily, while others clap their beak. Red-bellied woodpeckers at bird feeders often wave their formidable beaks at competing birds who get too close, clearly signaling "this seed's mine, you can't have it." The platypus uses its bill to navigate underwater, detect food, and dig. The bill contains electroreceptors and mechanoreceptors, causing muscular contractions to help detect prey. It

23936-431: The manner of gannets , the thin-walled highly pneumatized bones which must have fractured easily judging from the state of fossil specimens make such a mode of feeding unlikely, if not outright dangerous. Rather, prey would have been picked up from immediately below the ocean surface while the birds were flying or swimming, and they probably submerged only the beak in most situations. Their quadrate bone articulation with

24112-623: The metal used earlier, more heat is required. Once the technical challenge had been solved, iron replaced bronze as its higher abundance meant armies could be armed much more easily with iron weapons. All dates are approximate and conjectural, obtained through research in the fields of anthropology , archaeology, genetics , geology , or linguistics . They are all subject to revision due to new discoveries or improved calculations. BP stands for " Before Present (1950)." BCE stands for " Before Common Era ". Beak Although beaks vary significantly in size, shape, color and texture, they share

24288-401: The nature and behavior of pre-literate and non-literate peoples. Human population geneticists and historical linguists are also providing valuable insight. Cultural anthropologists help provide context for societal interactions, by which objects of human origin pass among people, allowing an analysis of any article that arises in a human prehistoric context. Therefore, data about prehistory

24464-442: The normal seasonal color change in the beaks of male black-headed gulls and indigo buntings . The beak of modern birds has a fused premaxillary bone, which is modulated by the expression of Fgf8 gene in the frontonasal ectodermal zone during embryonic development. The shape of the beak is determined by two modules: the prenasal cartilage during early embryonic stage and the premaxillary bone during later stages. Development of

24640-496: The north-east, while the ancient leopard seal Acrophoca is a remarkable species known from the south-east Pacific. Secondly, pinnipeds are limited to near-shore waters while pseudotooth birds roamed the seas far and wide, like large cetaceans, and like all big carnivores all three groups were K-strategists with moderate to very low population densities . Thus, direct competition for food between bony-toothed birds and cetaceans or pinnipeds cannot have been very severe. As both

24816-402: The older Paleogene forms. The sternum had the deep and short shape typical of dynamic soarers, and bony outgrowths at the keel 's forward margin securely anchored the furcula . The legs were proportionally short, the feet probably webbed and the hallux was vestigial or entirely absent; the tarsometatarsi (anklebones) resembled those of albatrosses while the arrangement of the front toes

24992-470: The only colours commonly found in these birds are black, white and various shades of grey. Some have patches of iridescent feathers, or brownish or reddish hues, but these are rare and limited in extent, and those species in which they are found (e.g. bitterns , ibises or the hammerkop ) are generally only found in freshwater habitat. If the pseudotooth birds are Galloanseres , phaeomelanins might be more likely to have occurred in their feathers, but it

25168-399: The other hand, the sternum , distal humerus , leg and foot bones of pelagornithids seem to show apomorphies typical of "higher waterbirds". While details of the braincase bones are held to be very informative phylogenetically , the skull features in which the two groups are similar are generally related to the point where the bill attaches to the skull, and thus might have been subject to

25344-485: The parents decide how to distribute food among the chicks in the nest. Some species, especially in the families Viduidae and Estrildidae , have bright spots on the gape known as gape tubercles or gape papillae. These nodular spots are conspicuous even in low light. A study examining the nestling gapes of eight passerine species found that the gapes were conspicuous in the ultraviolet spectrum (visible to birds but not to humans). Parents may, however, not rely solely on

25520-499: The pelagornithids adapted to an oceanic habitat independently from penguins and tubenoses, which instead have supraorbital salt glands . Their missing or vestigial hallux – like in ducks but unlike in pelicans which have all four toes fully developed and webbed – was held against a close relationship with pelicans. But as is known today, pelicans are closer to storks (which have a hallux but no webbing) than to pseudotooth birds and evolved their fully webbed toes independently. With both

25696-522: The pelican-stork group. It also provides leeway should the proposed separation of the Pelagornithidae into several families turn out to be appropriate. It is perhaps notable that when Boris Spulski established the Odontopterygia in 1910, he did this partly because he noted some of the similarities between pseudotooth birds and waterfowl listed above. Dasornis was long mistaken for a gastornithid , now strongly suspected to be very close indeed to

25872-451: The prenasal cartilage is regulated by genes Bmp4 and CaM , while that of the premaxillary bone is controlled by TGFβllr , β-catenin , and Dickkopf-3. TGFβllr codes for a serine/threonine protein kinase that regulates gene transcription upon ligand binding; previous work has highlighted its role in mammalian craniofacial skeletal development. β-catenin is involved in the differentiation of terminal bone cells. Dickkopf-3 codes for

26048-441: The presence of ultraviolet color) on their beaks. The presence and intensity of these peaks may indicate a bird's fitness, sexual maturity or pair bond status. King and emperor penguins , for example, show spots of ultraviolet reflectance only as adults. These spots are brighter on paired birds than on courting birds. The position of such spots on the beak may be important in allowing birds to identify conspecifics . For instance,

26224-605: The primitive dolphins of the Kentriodontidae or the shark-toothed whales , flourished contemporary with the Pelagornithidae and became extinct at about the same time. Also, the modern diversity of pinniped and cetacean genera evolved largely around the Mio- Pliocene boundary, suggesting that many ecological niches emerged or became vacant. In addition, whatever caused the Middle Miocene disruption and

26400-605: The pseudoteeth of the pelagornithids do not seem to have had serrated or otherwise specialized cutting edges, and were useful to hold prey for swallowing whole rather than to tear bits off it. Since the teeth were hollow or at best full of cancellous bone and are easily worn or broken off in fossils, it is surmised they were not extremely resilient in life either. Pelagornithid prey would thus have been soft-bodied, and have encompassed mainly cephalopods and soft-skinned fishes . Prey items may have reached considerable size. Though some reconstructions show pelagornithids as diving birds in

26576-418: The pseudotooth birds could have used the system of ocean currents and atmospheric circulation to take round-track routes soaring over the open oceans, returning to breed only every few years. Unlike albatrosses today, which avoid the tropical equatorial currents with their doldrums , Pelagornithidae were found in all sorts of climates, and records from around 40 Ma stretch from Belgium through Togo to

26752-401: The rapid evaporation of water vapor, and may also help to increase condensation within the nostrils themselves—both critical functions, since the nestlings get fluids only from the food their parents bring them. These opercula shrink as the birds age, disappearing completely by the time they reach adulthood. In pigeons , the operculum has evolved into a soft swollen mass that sits at the base of

26928-658: The regions and civilizations who developed a system of keeping written records during later periods. The invention of writing coincides in some areas with the beginnings of the Bronze Age. After the appearance of writing, people started creating texts including written records of administrative matters. The Bronze Age refers to a period in human cultural development when the most advanced metalworking (at least in systematic and widespread use) included techniques for smelting copper and tin from naturally occurring outcroppings of ores, and then combining them to cast bronze . These naturally occurring ores typically included arsenic as

27104-424: The rhamphotheca and the deeper layers of the dermis , which is attached directly to the periosteum of the bones of the beak. The rhamphotheca grows continuously in most birds, and in some species, the color varies seasonally. In some alcids , such as the puffins, parts of the rhamphotheca are shed each year after the breeding season, while some pelicans shed a part of the bill called a "bill horn" that develops in

27280-502: The rise of metallurgy, and most Neolithic societies on the whole were relatively simple and egalitarian. Most clothing appears to have been made of animal skins, as indicated by finds of large numbers of bone and antler pins which are ideal for fastening leather. Wool cloth and linen might have become available during the later Neolithic, as suggested by finds of perforated stones that (depending on size) may have served as spindle whorls or loom weights. In Old World archaeology,

27456-513: The same deposits as plotopterids and penguins , while younger forms were sympatric with auks , albatrosses, penguins and Procellariidae – which, however, underwent an adaptive radiation of considerable extent coincident (and probably caused by) with the final demise of the Paleogene-type trophic web. Although the fossil record is necessarily incomplete, as it seems cormorants and seagulls were very rarely found in association with

27632-486: The same principle as a human-devised nutcracker ). Birds that fish for a living have beaks adapted for that pursuit; for example, pelicans ' beaks are well adapted for scooping up and swallowing fish whole. Woodpeckers have beaks well adapted for pecking apart wood while hunting for their meals of arthropods . Birds may bite or stab with their beaks to defend themselves. Some species use their beaks in displays of various sorts. As part of his courtship, for example,

27808-428: The same species, and female American avocets have beaks which are slightly more upturned than those of males. Males of the larger gull species have bigger, stouter beaks than those of females of the same species, and immatures can have smaller, more slender beaks than those of adults. Many hornbills show sexual dimorphism in the size and shape of both beaks and casques , and the female huia 's slim, decurved bill

27984-428: The shrike tomial teeth are entirely keratinous. Some fish-eating species, e.g., the mergansers , have sawtooth serrations along their tomia, which help them to keep hold of their slippery, wriggling prey. Birds in roughly 30 families have tomia lined with tight bunches of very short bristles along their entire length. Most of these species are either insectivores (preferring hard-shelled prey) or snail eaters, and

28160-503: The sky if seen by prey in the sea. It is notable that at least the primary remiges , and often the other flight feathers too, are typically black in birds – even if the entire remaining plumage is completely white, as in some pelicans or in the Bali starling ( Leucopsar rothschildi ). This is due to the fact that melanins will polymerize , making all-black feathers very robust; as the largest forces encountered by bird feathers affect

28336-640: The small species for food on occasion, as they today harass albatrosses. From the Middle Miocene or Early Pliocene of the Lee Creek Mine, some remains of pseudotooth birds which probably fell victim to sharks while feeding are known. The large members of the abundant Lee Creek Mine shark fauna that hunted near the water's surface included the broadnose sevengill shark ( Notorynchus cepedianus ), Carcharias sand tiger sharks, Isurus and Cosmopolitodus mako sharks , Carcharodon white sharks,

28512-635: The sometimes biased accounts in Greek and Roman literature, of these protohistoric cultures. In dividing up human prehistory in Eurasia, historians typically use the three-age system, whereas scholars of pre-human time periods typically use the well-defined geologic record and its internationally defined stratum base within the geologic time scale . The three-age system is the periodization of human prehistory into three consecutive time periods , named for their predominant tool-making technologies: Stone Age , Bronze Age and Iron Age . In some areas, there

28688-405: The tip to the anterior edge of the nostrils, from the tip to the base of the skull, or from the tip to the cere (for raptors and owls) — and scientists from various parts of the world generally favor one method over another. In all cases, these are chord measurements (measured in a straight line from point to point, ignoring any curve in the culmen) taken with calipers . The shape or color of

28864-509: The two species of the moa-nalo genus Thambetochen , extinct giant flightless dabbling ducks from the Hawaiian Islands . In any case, the 2005 cladistic analysis uses a representative sample of Procellariiformes and recovers them as strongly supported clade in agreement with the current consensus. The presumed close relationship between bony-toothed birds and tubenoses can thus be disregarded after all. As regards "Pelecaniformes",

29040-503: The typical flapping flight of birds; their weight thus cannot be easily estimated. The attachment positions for the muscles responsible for holding the upper arm straightly outstretched were particularly well-developed, and altogether the anatomy seems to allow for an ability of holding the wings rigidly at the glenoid joint unmatched by any other known bird. This is especially prominent in the Neogene pelagornithids, and less developed in

29216-587: The use and provenance of materials, and genetic analysis of bones to determine kinship and physical characteristics of prehistoric peoples. The beginning of prehistory is normally taken to be marked by human-like beings appearing on Earth. The date marking its end is typically defined as the advent of the contemporary written historical record. Both dates consequently vary widely from region to region. For example, in European regions, prehistory cannot begin before c.  1.3  million years ago, which

29392-473: The very similarly-plumaged king and emperor penguins have UV-reflective spots in different positions on their beaks. The size and shape of the beak can vary across species as well as between them; in some species, the size and proportions of the beak vary between males and females. This allows the sexes to utilize different ecological niches, thereby reducing intraspecific competition . For example, females of nearly all shorebirds have longer bills than males of

29568-411: The well-developed hypotarsal crests, a supratendineal bridge on the distal tibiotarsus and the caudally closed ilioischiadic foramen. The actual phylogenetic tree depicts them in a polytomy with both Galloanserae and Neoaves. It has been suggested at times that the "teeth" of pelagornithids were homologous with true teeth on an at least molecular level, being derived from the same programs responsible for

29744-460: The whole area. "Palaeolithic" means "Old Stone Age", and begins with the first use of stone tools . The Paleolithic is the earliest period of the Stone Age . It extends from the earliest known use of stone tools by hominins c.  3.3  million years ago, to the end of the Pleistocene c.  11,650   BP (before the present period). The early part of the Palaeolithic

29920-428: The wildfowl family one of its former names: "Unguirostres" comes from the Latin ungus , meaning "nail" and rostrum , meaning "beak". Rictal bristles are stiff hair-like feathers that arise around the base of the beak. They are common among insectivorous birds, but are also found in some non-insectivorous species. Their function is uncertain, although several possibilities have been proposed. They may function as

30096-642: Was established based on a huge skull piece, which for long was placed in the Gastornithidae merely due to its size. Argillornis – nowadays recognized to belong in Dasornis – was described from wing bones, and generally included in the Sulae as part of the " Elopterygidae " – yet another invalid "family", and its type genus is generally not considered a modern-type bird by current authors. Some additional tarsometatarsus (ankle) bone fragments were placed in

30272-630: Was inaccessible for pinnipeds; just as many albatrosses today nest in the uplands of islands (e.g. the Galápagos or Torishima ). The bony-toothed birds probably required strong updrafts for takeoff and would have preferred higher sites anyway for this reason, rendering competition with pinniped rookeries quite minimal. As regards breeding grounds, giant eggshell fragments from the Famara mountains on Lanzarote , Canary Islands , were tentatively attributed to Late Miocene pseudotooth birds. As regards

30448-421: Was more like in fulmars . Typical for pseudotooth birds was a second toe that attached a bit kneewards from the others and was noticeably angled outwards. The "teeth" were probably covered by the rhamphotheca in life, and there are two furrows running along the underside of the upper bill just inside the ridges which bore the "teeth". Thus, when the bill was closed only the upper jaw's "teeth" were visible, with

30624-399: Was nearly twice as long as the male's straight, thicker one. Color can also differ between sexes or ages within a species. Typically, such a color difference is due to the presence of androgens . For example, in house sparrows , melanins are produced only in the presence of testosterone ; castrated male house sparrows—like female house sparrows—have brown beaks. Castration also prevents

30800-414: Was often assigned either to the gannet and cormorant suborder Sulae (which was formerly treated as superfamily Sulides in suborder Pelecanae), or to the Odontopterygia. The sternum of Gigantornis was placed in the albatross family (Diomedeidae) in the order of tube-nosed seabirds (Procellariiformes). The most extensive taxonomic and systematic confusion affected Dasornis . That genus

30976-606: Was unveiled in Lima . It had been found a few months earlier in Ocucaje District of Ica Province , Peru . According to paleontologist Mario Urbina , who discovered the specimen, and his colleagues Rodolfo Salas, Ken Campbell and Daniel T. Ksepka , the Ocucaje skull is the best-preserved pelagornithid cranium known as of 2009. Unlike the true teeth of Mesozoic stem -birds like Archaeopteryx or Ichthyornis ,

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